Chung says serves cost him against Wawrinka

South Korean teenager Chung Hyeon believes he could have defeated world number five Stan Wawrinka on Thursday if his serving had been better in the match.

The 19-year-old lost the US Open second round encounter in straight sets, but forced each set to a tiebreak and eventually lost 7-6(7-2), 7-6(7-4), 7-6(8-6) after a three-hour battle.

"If I'd been good enough to score aces against Wawrinka from the start, I probably would have won the match," Chung told the Yonhap News Agency.

"I am still trying to improve my serves. It can be intimidating and nerve-wracking to face a top-10 player, but it's something I have to overcome eventually. I am glad I got my lesson early."

"Now that I've played him, I can see why he's the No. 5 player in the world; he does everything so well.

"I felt pressure whenever I served, because I thought I'd have little chance of winning if I couldn't hold my serves against a player like that."

Chung defeated 23-year-old world number 95 James Duckworth, from Australia, 6-3, 6-1, 6-2 in the first round on Monday.

"Before the match, I wanted to pour out my last ounce of energy and play each set for an hour. I didn't want to back down so easily against a strong opponent,” Chung said of his match against Wawrinka.

“I think I stood my ground against Wawrinka because I kept each set going for an hour. But during the match, I just didn't have the presence of mind to think of anything."

Wawrinka, who will face 27-year-old Belgian Ruben Bemelmans in the third round, praised Chung and said the South Korean has a bright future.

"He's a really good player. Was a tough match today. He's moving well. He's a great fighter. He always tried to give you more balls to play or always tried to find a solution.

“He's playing well from the baseline. He can be really good, for sure. He's young and already playing well. He has a long way to go. You have to see how he's going to practice, improve, how he's going to work."